xref: /linux/Documentation/devicetree/bindings/powerpc/4xx/cpm.txt (revision e5451c8f8330e03ad3cfa16048b4daf961af434f)
1*d524dac9SGrant LikelyPPC4xx Clock Power Management (CPM) node
2*d524dac9SGrant Likely
3*d524dac9SGrant LikelyRequired properties:
4*d524dac9SGrant Likely	- compatible		: compatible list, currently only "ibm,cpm"
5*d524dac9SGrant Likely	- dcr-access-method	: "native"
6*d524dac9SGrant Likely	- dcr-reg		: < DCR register range >
7*d524dac9SGrant Likely
8*d524dac9SGrant LikelyOptional properties:
9*d524dac9SGrant Likely	- er-offset		: All 4xx SoCs with a CPM controller have
10*d524dac9SGrant Likely				  one of two different order for the CPM
11*d524dac9SGrant Likely				  registers. Some have the CPM registers
12*d524dac9SGrant Likely				  in the following order (ER,FR,SR). The
13*d524dac9SGrant Likely				  others have them in the following order
14*d524dac9SGrant Likely				  (SR,ER,FR). For the second case set
15*d524dac9SGrant Likely				  er-offset = <1>.
16*d524dac9SGrant Likely	- unused-units		: specifier consist of one cell. For each
17*d524dac9SGrant Likely				  bit in the cell, the corresponding bit
18*d524dac9SGrant Likely				  in CPM will be set to turn off unused
19*d524dac9SGrant Likely				  devices.
20*d524dac9SGrant Likely	- idle-doze		: specifier consist of one cell. For each
21*d524dac9SGrant Likely				  bit in the cell, the corresponding bit
22*d524dac9SGrant Likely				  in CPM will be set to turn off unused
23*d524dac9SGrant Likely				  devices. This is usually just CPM[CPU].
24*d524dac9SGrant Likely	- standby		: specifier consist of one cell. For each
25*d524dac9SGrant Likely				  bit in the cell, the corresponding bit
26*d524dac9SGrant Likely				  in CPM will be set on standby and
27*d524dac9SGrant Likely				  restored on resume.
28*d524dac9SGrant Likely	- suspend		: specifier consist of one cell. For each
29*d524dac9SGrant Likely				  bit in the cell, the corresponding bit
30*d524dac9SGrant Likely				  in CPM will be set on suspend (mem) and
31*d524dac9SGrant Likely				  restored on resume. Note, for standby
32*d524dac9SGrant Likely				  and suspend the corresponding bits can
33*d524dac9SGrant Likely				  be different or the same. Usually for
34*d524dac9SGrant Likely				  standby only class 2 and 3 units are set.
35*d524dac9SGrant Likely				  However, the interface does not care.
36*d524dac9SGrant Likely				  If they are the same, the additional
37*d524dac9SGrant Likely				  power saving will be seeing if support
38*d524dac9SGrant Likely				  is available to put the DDR in self
39*d524dac9SGrant Likely				  refresh mode and any additional power
40*d524dac9SGrant Likely				  saving techniques for the specific SoC.
41*d524dac9SGrant Likely
42*d524dac9SGrant LikelyExample:
43*d524dac9SGrant Likely	CPM0: cpm {
44*d524dac9SGrant Likely		compatible = "ibm,cpm";
45*d524dac9SGrant Likely		dcr-access-method = "native";
46*d524dac9SGrant Likely		dcr-reg = <0x160 0x003>;
47*d524dac9SGrant Likely		er-offset = <0>;
48*d524dac9SGrant Likely		unused-units = <0x00000100>;
49*d524dac9SGrant Likely		idle-doze = <0x02000000>;
50*d524dac9SGrant Likely		standby = <0xfeff0000>;
51*d524dac9SGrant Likely		suspend = <0xfeff791d>;
52*d524dac9SGrant Likely};
53